Nardilysin (NRDc), a metallopeptidase of the M16 family, presents, in vitro, cleavage specificity for basic residues. Depending on the cell type, it is cytoplasmic, exported or cell surface associated. As a new receptor for heparin-binding EGF-like growth factor (HB-EGF), NRDc was recently shown to be involved in cellular migration and proliferation. Since for those processes its enzymatic activity is not required, it is now evident that nardilysin fulfills at least two distinct functions, i.e. an HB-EGF modulator and a peptidase.